added use strict to all javascript files, and added correct html5 doctype
updated way to import utils from tools.js
refactored the update panel function to use array.forEach instead of for() loops ; create nodes as objects and not as inline html ; added ids on all the liElements based on the position in the tree.
code cosmetics
updated id element support ; added callback to display id of clicked element in log
added ugly hover on tabs and windows
added click to activate tab feature